Importation of malaria into the USSR from Afghanistan, 1981-89.

Between 1981 and 1989, a total of 7683 cases of Plasmodium vivax [corrected] malaria were imported into the USSR from Afghanistan, mainly by demobilized military personnel. For 23.8% of these cases the clinical manifestations appeared within a month of returning to the USSR, for 22.5% after 1-3 months, for 20% after 4-6 months, for 2% after > 1 year, and for 0.6% after > 2 years. For 13 patients the clinical manifestations of malaria appeared 3 years after returning from Afghanistan (up to 38 months). Nearly 69% of the patients did not take malaria prophylaxis at all while they were in Afghanistan, and 19% took chloroquine irregularly. Only 12.5% of the patients received a full course of prophylactic treatment with primaquine before leaving Afghanistan. A total of 56% of the cases were detected during the period most favourable for malaria transmission in the USSR (May-September) and of these, half were imported into formerly malarious areas of the country. Activation of a surveillance system greatly reduced the consequences of the massive importation of malaria, to which the local vectors were susceptible.

Use of the in vitro microtechnique for the assessment of drug sensitivity of Plasmodium falciparum in Sennar, Sudan.

In 1978, studies on the chloroquine sensitivity of Plasmodium falciparum were carried out in the district of Sennar, Sudan. The results of the in vivo tests showed parasites resistant at the RI level only, but the mean clearance time of trophozoites from the blood was higher than for strains found in many other areas of tropical Africa. The in vitro tests, using the microtechnique, indicated a lower sensitivity to chloroquine in the local P. falciparum isolates than in those of most other African countries. However, similar results have been reported from Ethiopia. The chloroquine sensitivity of P. falciparum from Sennar is close to the critical level of resistance. The in vitro microtechnique was also used to test for the sensitivity to Dabequin, 4-aminobenzo-quinoline, and was generally found to be a suitable and reproducible method, with a greater potential than the standard macro method. At parasite densities of over 100 000 asexual parasites per microlitre of blood the effect of a given concentration of chloroquine was related to the parasite density owing to the selective uptake of the compound by the parasitized cells.

Drug-resistant malaria--occurrence, control, and surveillance.

PIP: Chloroquine resistant strains of Plasmodium falciparum were initially reported during the early 1960s and are currently found in many areas of Asia and South America. The prevalence and degree of resistance are increasing in all affected areas, representing a serious setback to antimalaria programs. Alternative drugs are much more expensive and frequently more cumbersome to use. Consequently, it is essential that a concerted effort be made to arrest the spread of resistant strains by developing standardized national policies on drug use. The probable genetics and epidemiology of drug resistance are considered in this report, and attention is directed to the problems involved in its control. Antimalarial drugs interfere with important physiological functions of the parasites. Chloroquine and mepacrine apparently block acid proteases and peptidases in the phagosomes of intraerythrocytic parasites. Circumstantial evidence from "in vitro" tests suggests that strains of P. falciparum from various parts of the world, although primarily susceptible to chloroquine, exhibit, "a priori," different sensitivities. P. falciparum in the Sobat valley of Ethiopia and in central Sudan appears to be significantly less susceptible to chloroquine than the Uganda I strain. There are no indications yet of chloroquine resistance in P. vivax, P. malariae, or P. ovale. The relative prevalence of chloroquine resistant infections and the degree of resistance are still on the increase in all affected areas. The development of drug resistance in areas with previously susceptible parasites has thus far always been associated with the use of the particular medicaments. 4 main factors seem to be involved: the degree of drug pressure; the degree of host/parasite contact; the duration of drug pressure; and the type of drug used. The occurrence of chloroquine resistant falciparum malaria requires the urgent attention of the health authorities and that several operational measures be undertaken. Instructions must be provided concerning the principles of drug use in antimalaria programs in the event of the spread of drug resistance, and these instructions are reviewed. The methods for the monitoring of drug sensitivity are also reviewed. The World Health Organization (WHO) has developed global monitoring program, initially implemented in 1977 in the Southeast Asia Region. Program objectives are identified.^ieng